286
8.5.15
NMI Interrupts and DMAC
When an NMI interrupt is requested, burst mode transfer in full address mode is interrupted. An
NMI interrupt does not affect the operation of the DMAC in other modes.
In full address mode, transfer is enabled for a channel when both the DTE bit and the DTME bit
are set to 1. With burst mode setting, the DTME bit is cleared when an NMI interrupt is requested.
If the DTME bit is cleared during burst mode transfer, the DMAC discontinues transfer on
completion of the 1-byte or 1-word transfer in progress, then releases the bus, which passes to the
CPU.
The channel on which transfer was interrupted can be restarted by setting the DTME bit to 1 again.
Figure 8-36 shows the procedure for continuing transfer when it has been interrupted by an NMI
interrupt on a channel designated for burst mode transfer.
Resumption of
transfer on interrupted
channel
Set DTME bit to 1
Transfer continues
[1]
[2]
DTE= 1
DTME= 0
Transfer ends
No
Yes
[1]
[2]
Check that DTE = 1 and
DTME = 0 in DMABCRL
Write 1 to the DTME bit.
Figure 8-36 Example of Procedure for Continuing Transfer on Channel Interrupted by
NMI Interrupt
Содержание H8S/2631
Страница 28: ...xviii Appendix G Package Dimensions 1154 ...
Страница 341: ...316 Transfer SAR or DAR DAR or SAR Block area First block Nth block Figure 9 8 Memory Mapping in Block Transfer Mode ...
Страница 918: ...905 ø DREQ0 DREQ1 tDRQS tDRQH Figure 25 19 DMAC DREQ Input Timing ...
Страница 955: ...943 A 2 Instruction Codes Table A 2 shows the instruction codes ...